Mounting device for cushion plunger in hydraulic cylinder

Abstract

A device for mounting a cushion plunger to one end of the piston rod in a hydraulic cylinder, the cushion plunger constituting a part of a cushion mechanism installed to dampen the impact generated during the rotation of the piston in the hydraulic cylinder. The mounting device includes a recess provided at the end of the piston rod and adapted to partially receive the cushion plunger, a pin hole provided at the piston rod, the pin hole extending in a direction orthogonal to the recess such that it communicates with the recess, another pin hole perforated throughout the cushion plunger radially of the cushion plunger, the pin holes being aligned with each other at a state that the cushion plunger is received in position in the recess, a fling pin inserted into the pin holes being aligned with each other, the fling pin being adapted to fix the cushion plunger to the piston rod, and a clearance defined between the outer diameter of the fixing pin and the inner diameter of the pin hole of the cushion plunger.

What is claimed is: 
     
       1. A device for mounting a cushion plunger to one end of a piston rod in a hydraulic cylinder in combination with the cushion plunger and the piston rod, the cushion plunger constituting a part of a cushion mechanism installed to dampen the impact generated during rotation of the piston in the hydraulic cylinder, comprising: a recess provided at an end of the piston rod;   a pair of annular grooves respectively formed along an inner peripheral surface of the recess and an outer peripheral surface of the cushion plunger; and   a fixing ring received in the grooves, wherein the fixing ring has a cross-section that is elongated in a radial direction and includes flat axial sides and a rounded radially inner side and a rounded radially outer side, the grooves have cross-sections respectively corresponding to those of radially outer and radially inner portions of the fixing ring, the groove formed along the outer peripheral surface of the cushion plunger to support the radially inner portion of the fixing ring having an axial width sufficient to provide a predetermined clearance in an axial direction between the groove and the fixing ring, and the recess has an inner end being in contact with an end of the cushion plunger facing the inner end, wherein the fixing ring comprises two ring halves divided from a complete ring along a centerline of the ring.   
     
     
       2. A device for mounting a cushion plunger to one end of the piston rod in a hydraulic cylinder in combination with the cushion plunger and the piston rod, the cushion plunger constituting a part of a cushion mechanism installed to damp on the impact generated during the rotation of the piston in the hydraulic cylinder, comprising: a recess provided at the end of the piston rod and adapted to partially receive the cushion plunger;   a first pin hole provided at the piston rod, the first pin hole extending in a direction orthogonal to the recess such that it communicates with the recess;   a second pin hole perforated throughout the cushion plunger radially of the cushion plunger, the second pin hole being aligned with the first pin hole at a state that the cushion plunger is received in position in the recess;   a fixing pin inserted into the first and second pin holes being aligned with each other, the fixing pin being adapted to fix the cushion plunger to the piston rod; and   a clearance defined between the outer diameter of the fixing pin and the inner diameter of the second pin hole of the cushion plunger.